The present invention relates generally to surgical tools and more particularly for surgical tools used in conjunction with prostheses such as annuloplasty rings and bands.
Annuloplasty rings and bands are useful in a variety of surgical procedures, including mitral and tricuspid annular reduction. In these procedures, sutures are first placed around all or portions of the valve annulus at spaced intervals. Sutures passing through the annulus in regions in which reduction of the valve annulus is desired are spaced equidistant from one another, for example, at 4 mm intervals. These sutures are then brought through the annuloplasty ring or band more closely spaced than where they pass through the annulus, for example, 2 mm. The process of passing the sutures through the ring or band occurs while the prosthesis is held above the valve annulus. The ring is then moved down into contact with the valve annulus, causing contraction of the annulus, thus effecting a reduction in valve annulus circumference. This basic procedure is used to correct both mitral and tricuspid annular dilatation.
In order for the sutures to be passed through the annuloplasty ring, it is desirable that the ring be held in a fixture or tool of some fashion. One early tool was manufactured by Pilling Instruments, and took the general form of a cone provided with a circumferential groove near the base. The cone was also provided with longitudinal slits, so that the tool could be contracted to accept the ring around the circumference of the groove. The tool was adapted to be held by means of a threaded handle.
More recent holder designs are disclosed in U.S. Pat. No. 6,283,993, wherein sutures passing through the prosthesis are used to retain it in a circumferential groove on the holder. An alternative design is disclosed in U.S. Pat. No. 5,011,481, which employs radially and downwardly extending fingers in conjunction with sutures passing around the prosthesis to retain it on the holder. Yet another alternative design is disclosed in U.S. Pat. No. 5,522,884, in which an adjustable annuloplasty ring is retained on its holder by tightening the adjusting sutures within the ring to contract it into a circumferential groove on the holder.
Examples of flexible annuloplasty bands and rings are also disclosed in the above cited patents, all of which are incorporated herein by reference in their entireties.
The present invention is directed toward an improved holder for use with annuloplasty prostheses. The holder is specifically configured to assist the surgeon in performing the technique of mitral or tricuspid reduction, and is typically provided in conjunction with the annuloplasty ring or band, ready for use. The holder takes the general form of an oblate ring component having an upper surface, a lower surface and an outer circumferential surface corresponding generally to the configuration of a valve annulus. The prosthesis extends around at least a portion of this circumferential surface and is releasably retained alongside this surface during the passing of sutures through the prosthesis.
The present invention provides improvements directed to the mechanism for retaining the prosthesis on the holder during passage of the sutures and releasing the prosthesis after positioning on the valve annulus. In some embodiments, rather than retaining the annuloplasty ring to the holder by means of sutures passing through the annuloplasty ring, the ring is retained by means of downwardly extending penetrating members such as barbs, pins, pegs, or needles, which enter the annuloplasty prosthesis and retain it to the holder during passage of sutures through the prosthesis. These penetrating members may be fabricated of metal or molded plastic and are sufficiently rigid that they are not readily deflected outward to allow outward movement of the annuloplasty prosthesis away from the holder. The penetrating members may have sharpened or relatively blunt tips.
Some of the preferred embodiments employ a two-component holder in which the first component includes the circumferential surface around which the prosthesis is mounted and the second component carries the penetrating members. In these embodiments, the first component also typically includes radially extending projections that prevent the prosthesis from moving downward off of the penetrating members, until upward movement of the second component. In some of these embodiments, the first and second holder components are retained to one another, and in others, they are removable from one another. In some embodiments, the first and second holder components are retained adjacent to one another during passage of sutures through the prosthesis by means of a suture or sutures coupling the first and second components together. In these embodiments, the first and second components become movable relative to one another following cutting of the suture or sutures retaining them together. In other embodiments, a suture is employed in order to maintain the annuloplasty prosthesis on the holder, but release of the prosthesis is simplified by the provision of a cutting mechanism, integrated into the structure of the holder itself. The first and second holder components are preferably molded of generally rigid plastics but might in some cases be fabricated of metal or other materials.
The embodiments of the present invention generally are intended to provide a simplified and more easily employed mechanism for holding the annuloplasty prosthesis during passage of the sutures through the prosthesis and for releasing it from the holder after the ring has been moved downward into its intended location on the valves annulus.